Comparison of Bicarbonate-Based Versus Heparin-Based Impella® Purge Solution

The Impella® is a continuous axial flow pump that utilizes a purge solution to create a positive pressure barrier and prevent pump thrombosis. Bicarbonate-based purge solution (BBPS) is currently Food and Drug Administration-approved specifically for patients who are unable to tolerate heparin or have a contraindication to heparin, but solution choice between BBPS and heparin-based purge solution (HBPS) varies in clinical practice.

This study aims to compare the efficacy and safety of the BBPS versus HBPS when BBPS is used as the standard of care. The major endpoint was a composite outcome of pump thrombosis, stroke, and bleeding events.

This study was a retrospective analysis at 2 tertiary academic medical centers within the same health system (IRB Protocol #2023P002761). Adult patients were included if they required an Impella® device and received either the BBPS or HBPS for at least 72 hours between July 2022 and October 2023. The major endpoint was a composite outcome of pump thrombosis, stroke, and bleeding events. Pump thrombosis was defined as incidence of 2 or more purge pressures greater than 800 mmHg, the use of thrombolytic purge solution, or thrombus noted on imaging. Minor endpoints included intensive care unit (ICU) mortality, ICU length of stay, and vascular complications.

A total of 178 patients were evaluated of which 66 were included. The composite outcome occurred in 23 of 38 patients (60.5%) in the BBPS group and 17 of 28 patients (60.7%) in the HBPS group (P = 0.99). There was no difference in pump thrombosis, stroke, or bleeding events between cohorts. Vascular events were noted in 5 (17.9%) of HBPS and 13 (34.2%) of BBPS group (P = 0.14). Additional minor endpoints were not significantly different between the groups.

This study found no differences in pump thrombosis, stroke, and bleeding events in the BBPS versus HBPS group. Although these findings are supportive of utilizing BBPS as standard of care, larger, multi-center studies are needed to confirm differences in bleeding or thrombotic outcomes.